1. Field of the Invention
The present invention relates to an information recording head such as a printer head, which is equipped in an information recording apparatus and in which a plurality of recording elements for recording information by a dot matrix method are arranged in two rows.
2. Description of the Related Art
In an information recording apparatus for recording the information by the dot matrix method, the recording operation is performed by use of an information recording head, in which the recording elements for respectively forming the dots are arranged with constant intervals to each other on a straight line.
This kind of recording head is constructed such that the row of the recording elements is arranged in a longitudinal direction, which is perpendicular to a scanning direction of the recording head, with respect to a record medium such as a recording sheet, a recording paper or the like. Thus, the resolution of the dot matrix (i.e., the minimum interval between the adjacent dots) formed by the recording head, and especially the lateral resolution along the scanning direction is determined by the relative moving speed of the recording head with respect to the recording medium and the interval of the discharge of the ink. On the other hand, the longitudinal resolution along the longitudinal direction perpendicular to the scanning direction is fixed by the interval of the arrangement in the longitudinal direction of the recording head constructing the recording head. Therefore, in order to realize a recording operation in which the longitudinal resolution is variable, it is necessary to prepare a plurality of recording heads, whose intervals of the arrangements in the longitudinal directions of the recording elements are different from each other.
By the way, because of the size of the recording element and the restriction on a production or process of the recording element (e.g., the easiness of the process, the strength achieved by the process), there may be raised a case where the distance (interval) between the adjacent recording elements cannot be reduced to be less than a predetermined value, i.e., a case where the longitudinal resolution cannot be improved.
Thus, there is a method of reducing the interval between the adjacent dots in the longitudinal direction by arranging the recording head such that the row of the recording elements is inclined with respect to the scanning direction by an angle .theta.. Namely, assuming that the interval between the adjacent recording elements is x and the inclination angle is .theta., the interval of the dots formed by this row of the recording elements becomes x Sin .theta., so that the interval of the dots becomes its maximum when the inclination angle .theta. is 90 deg! and the interval of the dots decreases as the inclination angle .theta. approaches 0 deg!. In this structure, even in case of a single recording head, by adjusting the inclination angle .theta. of the row of the recording elements with respect to the scanning direction, it is possible to set the longitudinal resolution voluntarily. However, in this structure, in case that the range to form the dots (i.e. the longitudinal width of the dots) by one scanning operation is set in advance, since the more number of the recording elements should be arranged in one row as the longitudinal resolution is to be increase, there is a problem that the size of the recording head becomes significantly large.
As a countermeasure to this problem, there is a recording head in which the recording elements are arranged in two rows in parallel to each other. In this recording head, since the recording elements are arranged such that the dots formed by the recording elements in both of the two rows are arranged at equidistant intervals in the longitudinal direction alternatively to each other. Thus, as compared with the case that the recording elements are arranged in one row, the length in the row direction can be reduced to be about half.
By the way, as the resolution required in the recording apparatus becomes higher, the more accurate designing and processing are required for the production of the recording head. Thus, since the time and trouble are required for the development and the manufacture of such a recording head, it is desired to commonly use the recording head in cases where the resolutions are different from each other.
However, in case of the recording head having the two rows of the recording elements, it is not possible to voluntarily incline the row of the recording elements with respect to the scanning direction as in the case of the recording head having just one row of the recording elements. Thus, since the different recording heads should be manufactured for each longitudinal resolution to be realized, the trouble and cost cannot be reduced in this case of the recording head having the two rows, which is a problem.
That is, in case of the recording head having one row of the recording elements, if the row of the recording elements is inclined with respect to the scanning direction, the intervals in the longitudinal direction of the dots formed by the recording elements are shortened homogeneously. On the contrary to this, in case of the recording head having the two rows, if the two rows are inclined with respect to the scanning direction, the intervals in the longitudinal direction of the dots formed by the recording elements become heterogeneous. Consequently, the different recording heads should be prepared for each longitudinal resolution to be realized.